I have an entire anime of dumb girls. Teekyu. Not a single one of them have more than three brain cells each.And that's being REALLY generous with the numbers.

I have a bit of an issue with the inclusion of Misa from Death Note. Overall, she might be considered dumb, but she is also pretty dang shrewd in the way she used Ren as a bargaining chip with Light. Her infatuation with Light/Kira was her biggest problem. She let that cloud her thought processes.

the girl from uhh peach girl...like both of them O_O really ANNOYING.....
also....
Kagome...yes yes....she's the main character...but she gets too much into trouble
she always calls "inuyasha! inuyasha! SAVE ME!"
and inuyahsa gets hurt and blablabla

Ayano Kannagi from Kaze No Stigma. I don't think she's particularly dumb, but......dear God, that voice......everytime she opens her mouth, I want to punch a baby. She's always reprimanding Kazuma, and YELLING FOR NO REASONNNNNN. She constantly does things without thinking first, and, I dunno, maybe its because I was watching the English dub, and maybe that's part of her character, but I just have a huge issue with her.

i think not. She was simply born in the ocean and is unwise to the ways of the surface world. Shes bilingual (Japanese and English) and she can do college level mathematics, if you watched that episode. Plus her social skills progress throughout the show. Definitely NOT the dumbest character in anime, just new to her element is all.